Electric lamp.



I. LADOPF. ELECTRIC LAMP. APPLICATION TILED NOV. 28, 1904.

Patented Feb.23,-1909.

INVENTOR Isa darladaff ATTORIVEKS UNITED s raa as arnnr orricn.

ISADOR LADOFF, OF SOHENECTADY, NEWv YORK ELECTRIC LAMP.

hto. 913,016.

Specifiationof Letters Patent.

Patented Feb. 23, 1909.

Application filed November 28, 1904. Serial No. 234,560.

cation, in which similar characters of reference indicate corresponding parts in all the figures.

Figure 1 is a front elevation of an arc lamp equipped with my invention and adapt ed to be used in connection with alternating currents: Fig. 2 is an enlarged fragmentary eleyation of the carbonsand mantle; Fig. 3

' is. an elevation somewhat'similar to Fig. 2,

.butshowing the mantle adjusted for use with a direct current.

The body 5 of the lamp, the rods 6 depending therefrom, the base- 7 and the carbon holder 8 may all be of any desired construction. The carbons are shown at 9, 10. The mantle holder is shown at 11 and consists preferably of metallic wire. This mantle holder is provided with portions 12, 131 projecting laterally therefrom and bent into annular form as shown, The mantle 15 is supported upon these annular portions. Where alternating currents are employed it is preferable that the mantle be so disposed relatively to the carbons 9, 10 that the ends of the latter are slightly exposed, as indicated in F ig. 2. hen, however, a direct current is employed. it is preferable that the mantle be so adjusted that only one of the carbons is exposed at its tip or crater, as will be understood from Fig. 3.

In the mantle above described the composition is substantiallythe same as in the ordinary Welsbach mantle; that is to say, an oxid of cerium, lanthanum, thorium, germanium. zirconium and didymium is used for impregnating a fabric, which is after ward. burned oil so as to leave the oxid in the manner well understood in the art. The 'arious oxide of the rare'metals above mentioned may be used singly or admixed together. I find that a good plan is to usev ninety-nine per cent. or more-of thorium oxid admixed with one per cent. or less of cerium oxid. The cerium oxid may be formed by admixing a small proportion of ceriumnitrate with the thorium oxid, and when the mantle is flamed or burned off the cerium nitrate is converted into cerium oxid, nitro' gen dioxid (X0 escaping. 'here alternating currents are employed. and consequently the temperature of both carbons is approximately the same. I find it advisable to adjust the mantle as indicated in Fig. 2. 'hen, however. direct current is used (in which thepositivc carbon is of a higher temperature than the negative carbon), I make use of the high luminosity of the positive carbon. and I adjust themantlc as shown in Fig. 3.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In an illuminating de'icc, the combination of a pair of electrodes, between which an arc may be formed. with an open mesh mantle of rare earth oxids disposed in a position to surround the arc and be heated thereby.

2. In an illuminating device. the combination of a pair of'electrodes. between which an arc may be formed. with an open mesh mantle of rare earth oxids disposed in a position to surround the arc and be heated thereby. and means independent of the electrodes for supporting the mantle out of electrical communication with the electrodes. In testimony whereof I have signed my nameto this specification in the presence of two subscribing witnesses.

- ISADOR LADOFF. Witnesses:

G. Isaac G.-xnn11.ow1r7..

Gan Jaconsox. 

